1. Field of the Invention
The present invention relates to a retractable lens and an optical element holding device thereof, and particularly to a retractable photographing lens and a swingable lens retracting device thereof. The swingable lens retracting device retracts a part of a plurality lens elements, constituting a photographing optical system, to a position deviating from the photographing optical axis of the photographing optical system when the photographing lens is fully retracted.
2. Description of Prior Art
Retractable photographing (imaging) lenses incorporated in optical devices, such as digital cameras, are generally zoom lenses that effect zooming by position variation of a plurality of lens groups thereof. The retractable lens completely retracts into the device body when the optical device is not in use, and extends out when in use. Accordingly, relative to a fixed zoom lens that is bulky and heavy, the retractable lens has the advantages of compactness and portability. In a conventional retractable photographing lens including a plurality of optical elements, one or more movable optical elements thereof are moved only along a common photographing optical axis. Therefore, as shown in FIG. 1 of the attached drawings, when such a retractable photographing lens is fully retracted, it is impossible to make the length of the photographing lens smaller than the sum of the thickness of all the optical elements. Accordingly, the length of the device body incorporating this retractable lens also cannot be further reduced.
To address the above problem, that is, to further minimize the retractable photographing lens, various designs, such as those disclosed in U.S. Pat. No. 5,166,716 and US Patent Application No. 20030156832, have been proposed. In these designs, when the retractable photographing lens is fully retracted, a part of the plurality of lens elements thereof is retracted to a position deviating from a common photographing optical axis of the photographing optical system. The optical axes of these deviating lens elements are arranged to be parallel to the common photographing optical axis so as to reduce the length of the device body. However, at the same time, the height of the device body may be increased to an unacceptable level for a compact optical device. Further, in these designs, the structure and driving mechanism of a lens retracting device for holding the deviating lens element are generally complicated, which results in tedious assembly and increased cost.
Accordingly, to overcome the problems present in the prior art, it is desired to provide a new optical element holding device for a retractable lens that reduces the length and height of an optical device incorporating the retractable lens, and is simple in structure and easy in assembly.